In perennial agriculture, such as coffee plantation, weeds are controlled by hand, mechanized, and chemical weeding and their combinations. Methods that differ in terms of efficiency and costs have been evaluated; however, the influence of these methods on the soil chemical conditions has not been studied, particularly in the long term. This study aimed to evaluate the effect of different weed control methods on soil acidity components of a coffee plantation on a dystroferric Red Latosol in an experiment installed at EPAMIG Experimental Station, in São Sebastião do Paraíso, MG, Brazil. Seven weed control treatments were evaluated: mower (MW), coffee tandem disk harrow (TD), rotary tiller (RT), post (CH) and pre-emergency herbicide (RH) application, hand hoe (HH) and no weed control (NC). The treatments were evaluated in a randomized block design with three repetitions. Soil samples were collected every two years, for each treatment, starting in 1980, in the 0-0.15 to 0.15-0.30 m soil layers and assessed for pH, Al3+ (mmol c dm-3), effective acidity (H + Al) (mmol c dm-3), and Al3+ saturation (%). The HR system increased Al3+ content and saturation and the effective acidity and reduced the pH, compared to the other weed control methods, especially the control (NC). Contrarily to the RH, the NC treatment resulted in higher pH values, Al3+ content and Al3+ saturation in both soil layers. The MW treatment was closest to the SC treatment, while the other weed control systems did not differ significantly.
weed management; chemical soil quality
